ML16162A627
| ML16162A627 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/24/1985 |
| From: | Nicolaras H Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8510040565 | |
| Download: ML16162A627 (45) | |
Text
Dockets Nos. 50-269, 50-270 and 50-287 LICENSEE:
Duke Power Company FACILITY:
Oconee Nuclear Station, Units 1, 2 and 3
SUBJECT:
SUMMARY
OF MEETING WITH DUKE POWER COMPANY ON COST/BENEFIT EVALUATION OF THE REACTOR VESSEL COOLANT INVENTORY TRACKING SYSTEM FOR THE OCONEE NUCLEAR STATION, UNITS 1, 2 AND 3 Duke Power Company (the licensee) requested to meet with the staff to present a new risk analysis relating to the cost/benefit evaluation of reactor vessel coolant inventory tracking system for the Oconee Nuclear Station. The staff met with the licensee on November 7, 1984 and the list of participants is included as Enclosure 1. Enclosure 2 lists the agenda which the licensee followed to make his presentation and Enclosure 3 is a copy of the viewgraphs presented during the meeting. On January 17, 1985, the NRC staff wrote the licensee a letter stating that "the generic requirement for reactor coolant inventory monitoring system was established after an extensive NRC review which included interaction with the industry during the decision process.
Implementation of this requirement has been substantially completed on a majority of pressurized water reactors. A request for plant - specific deviation from this generic requirement must be supported by a comprehensive safety analysis and a probalistic risk assessment..."
Helen Nicolaras, Project Manager Operating Reactors Branch #4 Division of Licensing
Enclosures:
As Stated cc w/enclosures:
See next page ORB#4:DL HNip laras;cr 7/ 85 851004055, a50724- '7"t I-PDR ADUJCK 05000269,.
DR,_
MEETING
SUMMARY
DISTRIBUTION Licensee: Duke Power Company
- Copies also sent to those people on service (cc) list for subject plant(s).
Docket File NRC PDR L PDR ORB#4 Rdg Project Manager -HNicolaras JStolz BGrimes (Emerg. Preparedness only)
OELD Ejordan, IE ACRS-10 PMorriette NRC Meeting
Participants:
HNicolaras BBernero LRubenstein RJones HLi GLainas JStolz THuang LPhillips AThadani EChelliah JShea
10k REG&,.
UNITED STATES o,
NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 Dockets Nos. 50-269, 50-270 and 50-287 LICENSEE:
Duke Power Company FACILITY:
Oconee Nuclear Station, Units 1, 2 and 3
SUBJECT:
SUMMARY
OF MEETING WITH DUKE POWER COMPANY ON COST/BENEFIT EVALUATION OF THE REACTOR VESSEL COOLANT INVENTORY TRACKING SYSTEM FOR THE OCONEE NUCLEAR STATION, UNITS 1, 2 AND-3 Duke Power Company (the licensee) requested to meet with the staff to present a new risk analysis relating to the cost/benefit evaluation of reactor vessel coolant inventory tracking system for the Oconee Nuclear Station. The staff met with the licensee on November 7, 1984 and the list of participants is included as Enclosure 1. Enclosure 2 lists the agenda which the licensee followed to make his presentation and Enclosure 3 is a copy of the viewgraphs presented during the meeting. On January 17, 1985, the NRC staff wrote the licensee a letter stating that "the generic requirement for reactor coolant inventory monitoring system was established after an extensive NRC review which included interaction with the industry during the decision process.
Implementation of this requirement has been substantially completed on a majority of pressurized water reactors. A request for plant - specific deviation from this generic requirement must be supported by a comprehensive safety analysis and a probalistic risk assessment..."
Helen Nicolaras, Project Manager Operating Reactors Branch #4 Division of Licensing
Enclosures:
As Stated cc w/enclosures:
See next,page MEETING WITH DUKE POWER COMPANY ON REACTOR VESSEL INVENTORY TRACKING SYSTEM NOVEMBER 7, 1984 NAME TITLE AFFILIATION Helen Nicolaras Project Manager NRC/NRR/DL Bud Gerling Jr. Engr.
PRA/DUKE Bob Bernero Dir. DSI, NRR NRC/NRR/DSI L. S. Rubenstein AD, Core/Plant Supt.
NRC/NRR/CPS K. S. Canady Manager, Nuclear Engr.
Duke Power Co.
Paul Guill Assoc. Eng./Lic.
Duke Power Co.
G. B. Swindlehurst Nuclear Engineer Duke
-R.
C. Jones Nuclear Engineer NRC/NRR/DSI/RSB R. K. Frahm Section Leader RRAB/DST/NRC Hulbert C. Li Reactor Engineer NRC/DSI/ICSB Jan Kozyra Licensing Engineer CP&L Gus Lainas AD/Operating Reactor NRC/NRR/DL John F. Stolz B/C ORB#4/DL NRC/NRR/DL Tai Huang Nuclear Engineer NRC/NRR/DSI/CPB Larry Phillips Section Leader NRC/NRR/DSI/CPB Larry Reed Sup. Pra Duke Power Ashok Thadani Branch Chief NRC/DST/RRAB Erulappa Chelliah Nuc. Sy. Eng.
NRC/DST/RRAB Jim Shea Project Manager NRC/DL/0R85 AGENDA OBJECTIVE & 'APPROACH OF ANALYSIS OVERVIEW OF ICC INSTRUMENTATION SYSTEM CORE DAMAGE SEQUECE EVALUATION QUANTIFICATION OF SEQUENCES ASSESSENT OF AVERTED DOSE RESULTS & CONCLUSIONS PRESENTATION PRA EVALUATION OF REACTOR COOLANT INVENTORY MONITORING SYSTEM OCONEE NUCLEAR STATION NOVEMBER 7, 1984 WASHINGTON, DC 1
AGENDA INTRODUCTION K. S. CANADY OBJECTIVE a APPROACH OF ANALYSIS L. A. REED OVERVIEW OF ICC INSTRUMENTATION SYSTEM L. A. REED CORE DAMAGE SEQUENCE EVALUATION R. J. GERLING QUANTIFICATION OF SEQUENCES L. A. REED ASSESSMENT OF AVERTED DOSE L. A. REED RESULTS & CONCLUSIONS L. A. REED 2
DEFINITION ICC o SUBCOOLED o CORE EXIT TEMP o RC INVENTORY TRACKING
+ RC PUMP CURRENT
+ LEVEL RCIMS LOOPS (A&B)
VESSEL 3
OBJECTIVE TO DETERNIME THE SAFETY BENEFIT, USING PRA TECHNIQUES, OF IMPLEMENTING RCIMS
£4
APPROACH UTILIZED OCONEE PRA STUDY
- TO IDENTIFY ACCIDENT SEQUENCES WHERE THE RCIMS COULD CHANGE THE COURSE OF A CORE DAMAGE SEQUENCE
- TO QUANTIFY POSSIBLE CHANGES IN THE FREQUENCIES OF AFFECTED SEQUENCES BECAUSE OF RCIMS
- TO DETERMINE THE AVERTED DOSE TO THE PUBLIC BECAUSE OF RCIMS APPLIED THE PROPOSED NRC COST/BENEFIT GUIDELINE TO ESTIMATE THE $ BENEFIT DERIVED FROM RCIMS 5
OCONEE PRA o A PRA STUDY JOINTLY SPONSORED BY DUKE AND NSAC.
o THE STUDY WAS COMPLETED IN 1983 AND PUBLISHED IN JUNE, 1984, o IN THE TERMINOLOGY OF NUREG/CR-2300, THE OCONEE PRA IS A LEVEL 3 WITH ANALYSES OF EXTERNAL EVENTS.
6
ICC INSTRUMENTATION
- 1.
CONTROL BOARDS:
PARAMETER BASED
- 2. SPDS: FUNCTION BASED
- 3. ICC:
PARAMETER BASED 7
CONTROL BOARD INSTRUMENTATION INDICATION SUBCOOLED MARGIN (RC LOOPS & CORE EXIT)
CORE EXIT THERMOLCOUPLES PRESSURIZER LEVEL/RC PRESSURE 8
ICC INST (CONT)
SPDS FUNCTIONS SUBCRITICALITY ICC HEAT SINK RCS INTEGRITY CONTAINMENT INTEGRITY RCS INVENTORY COLOR GRAPHIC DISPLAYS VIA PLANT COMPUTER DISPLAY IS GENERATED FROM ON-LINE DATA THAT HAS BEEN PROCESSED VIA A LOGIC NETWORK 9
ICC INST (CONT)
ICC INDICATION SUBCOOLED MARGIN CORE EXIT THERMOCOUPLES INVENTORY TRACKING RCIMS RCP CURRENT DEDICATED PLASMA DISPLAY (1 FOR EACH OF TWO TRAINS)
DIRECT INPUT TO READOUTS FROM SENSORS VIA MICRO PROCESSOR 10
OCONEE PRIMARY SYSTEM ODRE RELIEF VALVE NOZZLES CORE TANK A VENT LINE Ft60D SPRAY LINE RESSURIZEF PRESSURE TAP yOTRTD PUM AI
-- AUXILIARY PUMP B2 FLOW FEEDWATER
-PRESSURE TAP TAP INLET THOyRTD t
lHP SURGE LINE INJECT FLOW TAP AUXILIARY FEEDWATER INLET LINJECTION NOZZLE eUPL kE~O MAIN FEEDWATER HEADER TCOLDRTD DECAY HEAT NOZZLE SE A T
NP INJECTION NDZZLE GENERATOR 0
REACTOR VESSEL
- STEAM, GENERATOR OLOOP A
LOOP B 11i
CONTROL BOARD SMM CETS L/P SPDS ICC SUBCRITICAL
.SM ICC CETS RC INTEGRITY RCIMS HEAT SINK RPM RC INVENTORY CONTAINMENT INTEGRITY 12
CONTROL ROOM LAYOUT CETs UNIT IOARD uSNI I ol CONTTROLONROSBAR 33
1 UB2 1UB1 PRZ RELIEF VALVs STATUS ICC DISPLAYS SPos TRAIN TRAIN A
B PRZ LEVEL RC PRESS CETS ICC li bhb SMM KEYPADS 43
SEUENCESEllCTON o DMINED THE NINIML CUT SETS THAT COMPRISE THE CORE-4ELT SEQUENCES.
o THESE MINIM4L CUT SETS ARE DUE TO VARIETY OF INITIATING EVENTS COPONENT FAILURES, HUMN ERRORS.
o CATEGORIZED MINIMAL CUT SETS INTO GROUPS ON THE BASIS POTENTIAL EFFECT BY RCIMS.
15
INITIATING -
EVENT DESCRIPTION (INTERNAL)
A LARGE LOCA
+ R SG TUBE RUPTURE RPVRUPTURE REACTOR-VESSEL RUPTURE
+ S SMALL LOCA
+ T (ALL)
SUMMATION OF ALL TRANSIENT FREQUENCIES T (NO LOFW)
SUMMATION OF TRANSIENT FREQUENCIES NOT INVOLVING LOSS OF FEEDWATER AS AN INITIATOR.
+ T2 LOSS OF MFW T3 PARTIAL LOSS OF MWF (ASSUMED TO BE LOSS OF 1 TRAIN)
+ T5FEEDF FAILURE OF OFFSITE POWER DUE TO GRID OR FEEDER FAILURE T5SUBF FAILURE OF OFFSITE POWER DUE TO 230-kV SUBSTATION FAILURE (BOTH BUSES)
+ T6 LOSS OF IA
" T8 SPURIOUS ES ACTUATION SIGNAL T9 STEAMLINE BREAK
+T1O LARGE FEEDLINE BREAK
+T11 LOSS OF ICS POWER FROM BUS KI T12 LOSS OF LPSW T12 LOSS OF LPSW BY THE TRANSFER OF LPSW-108 T12 LOSS OF LPSW BY FAILURES OTHER THAN LPSW-108
+T13 SPURIOUS LOW PRESSURIZER PRESSURE SIGNAL T14 LOSS OF 4-kV SWITCHGEAR 3TC
+ATWS NOTE:
+
APPEARS IN THE SEQUENCES SELECTED FOR QUANTIFICATION 16
INITIATING -EVENTS (CONT)
(EXTERNAL)
EARTHQUAKES EXTERNAL FLOODS TORNADOES
+ FIRES
+ INTERNAL FLOODS NOTE:
+
APPEARS IN THE SEQUENCES SELECTED FOR QUANTIFICATION 17
SEQUENCE SELECTION (CONT)
GROUP 1 INITIATING EVENTS OR SYSTEM FAILURES ARE SUCH THAT RCIMS WILL HAVE NO EFFECT EXAMPLE:
RV RUPTURE, EXTERNAL FLOODING, LARGE LOCA WITH FAILURE OF SUMP RECIRCULATION GROUP 2 COMPRISED OF THOSE SEQUENCES WHERE RCIMS IS EXPECTED TO PROVIDE AN ADDITIONAL OPPORTUNITY FOR POSSIBLE RECOVERY EXAMPLE:
SEQUENCES WHERE OPERATORS FAILED TO INITIATE HPI GROUP 3 COMPRISED OF THOSE SEQUENCES WHERE THE IMPACT OF RCIMS IS UNCLEAR AND REQUIRED ADDITIONAL INVESTIGATION EXAMPLE: NATURAL CIRCULATION COOLDOWN, OVER THROTTLING OF HPI --- SMALL BREAK EVENTS, OVER THROT TLING OF LPI --- LARGE BREAK LOCA EVENTS, OVERCOOLING EVENTS.
18
SEQUENCES SELECTION (CONT)
THE SEQUENCES THAT WERE RETAINED WERE THOSE WHERE THE OPERATOR COULD AFFECT THE OUTCOME THROTTLE HPI INITIATE HPI 19
SEQUENCE SELECTION (CONT) o NUMBER OF CUTSETS CONSIDERED IN THE HUNDREDS o NUMBER OF CUTSETS RETAINED 62 20
SBLQCA E T TREE S
K U
OT X
S = SB LOCA INITIATOR K = REACTOR TRIP U = INITIATION OF HPI OT = THROTTLE OF HPI X = LONG TERM COOLING EXNPLE CUTSE[
S*HP
- RECOVERY 21
TPANSIEW EVEN TREE T
K E
Ul X TYPE NCM CM Ns T = TRANSIENT INITIATOR K = REACTOR TRIP E = EMERGENCY FW U = INITIATION OF HPI X = LONG TERM COOLING T2* EFW
- UTHPIH
- RECOVERY 22
-SEQU ENCE SELECTON RESULTING CUTSETS CATEGORY 1 SMALL BREAK LOCA, HPI AVAILABLE, HPI OVERTHRO]TLE) 21 CUTSETS CATEGORY 2 SEQUENCES WHERE LOSS OF ALL FEEDWATER OCCURRED, FAILS TO INITIATE HPI.
41 CUTSETS 23
SEQUENCE QUANTIFICATION o OPERATOR/SEQUENCE INTERFACE INSTRUMENTATION/CONTROLS PROCEDURES OPERATING SHIFT STRUCTURE TRAINING & EXPERIENCE o ASSIGN PROBABILITIES OVERTHROTTLED (OT)
FAIL TO RECOVER FROM ANOT CONDITION (x(w/LM)
FAIL TO INITIATE HPI SYSTEM (x3w/LM).
24
QUANTIFICATION (CONT)
A TASK OF DETERMINING HUMAN RELIABILITY ESSENTIALY DETERMINING THE WORTH OF AN ADDITIONAL READOUT DIANOSIS NOT IMPORTANT USED THE HR HANDBOOK I.E. TASK ORIENTED 25
EVENTS PROCEDURES 2ROs MONITORING SRO>
RCS ST HPI FAILED o OT OR OPS/TE~
o NOT INITIATED SUPPORT CTRS 26
QUANTIFICATION (CONT)
CATEGORY I (THROTTLE) 1 l*lOTI*[R/WOI=
[ ]*[OT]*[R/W1=
CATEGORY II (INITIATE)
[
]*lR/WO=
2 ]*[R/W =
27
CONSEQUENCES ANALYSIS DEFINITIONS o CORE DAMAGE CORE MELT SUSTAINED CORE UNCOVERY o CORE MELT BINS (CM)
A CATEGORIZATION OF SIMILAR CONTAINMENT EFFECTS INTO GROUPINGS CALLED BINS. ACCIDENT SEQUENCES ARE REVIEWED AND PLACED IN THE APPROPRIATE BIN FOR EXAMPLE: ALL SEQUENCES THAT RESULT IN A CORE MELT IN < 2 HOURS AND RC PRESS OF
< 400 PSIG ARE GROUPED INTO BIN 1 o PLANT DAMAGE STATES (PDS)
A CATEGORIZATION OF PLANT DAMAGE CONDITIONS INTO "STATES" THAT HAVE VERY SIMILAR CHARACTERISTICS IN TERMS OF A PARTICULAR RELEASE CATEGORY FOR EXAMPLE: ALL CM BIN 1 SEQUENCES W/O REACTOR BLD.
SPRAY BUT REACTOR BLD. COOLING UNIT IS AVAILABLE ARE GROUPED INTO THE PDS 1B 28
THE NEED FOR CATEGORIZING INITIATING CMB PDS RC WS CONSEQUENCE CURVES EVENTS 01020 24 24C-29 5
RC-18
CONSEQUENCE ANALYSES o PARTITION AFs INTO CORE DAMAGE BINS THEN INTO PLANT DAMAGE BINS o CALCULATE THE (F)
REDUCTION IN EACH OF THE SIX RELEASE CATEGORIES (RC) o DETERMINE MREM AVERTED FOR EACH RC o TOTALED MREM AVERTED FROM ALL RC's 30
CONSEQUENCE (CONT)
CMBIN PDS RC CATEGORY I 1
mIA 1A IIB B
D 2
CATEGORY II V
B 5
C VI D
31
RESULTS o REDUCTION IN CORE DAMAGE FREQUENCY ATTRIBUTABLE TO RCIMS IS 1.4 % OR 3.7 x 10- /YR o AVERTED POPULATION ROSE ATTRIBUTABLE TO RCIMS IS 0.11% OR 0.14 MREM/YR 32
CONCLUSIONS o NO SIGNIFICANT REDUCTION IN OVERALL CORE DAMAGE FREQUENCY CAN BE ATTRIBUTED TO RCIMS o AVERTED PUBLIC DOSE RESULTING FROM THE IMPLEMENTATION OF RCIMS IS NEGLIGIBLE o APPLICATION OF COST BENEFIT PERSPECTIVE SUGGESTS THAT THE COST OF THE SYSTEM IS OVERWHELMING COM PARED TO THE BENEFIT AND CANNOT BE JUSTIFIED ON THIS BASES 33
CONCLUSIONS (CONT) o OTHER PERSPECTIVES NOT USEFUL WHEN RCPs ARE RUNNING OR RC VENTS ARE OPEN EQUIPMENT/CONTROL ROOM SPACE IS AT A PREMIUM THE RCIM SYSTEM IS PARASITIC IN THAT IT USES PLANT RESOURCES AND OPERATOR TIME WITHOUT PROVIDING AN EQUITABLE RETURN 34
RCIMS 35
STATUS o IMPLEMENTATION SCHEDULE PROVIDED BY 9/6/84 LETTER o CURRENTLY ON SCHEDULE o FINAL DESIGN DESCRIPTION - JULY, 1985 o EOP TECHNICAL GUIDELINES DUKE SUBMITTAL - MARCH, 1986 NRC APPROVAL - JULY, 1986 o IMPLEMENTATION LETTER UNIT 1 - NOVEMBER, 1986 UNIT 2 - MARCH, 1987 UNIT 3 - MARCH, 1986 0 INSTALLATION COMPLETED - JUNE, 1987
MEETING
SUMMARY
DISTRIBUTION Licensee:
Duke Power Company
- Copies also sent to those people on service (cc) list for subject plant(s).
Docket File NRC PDR L PDR ORB#4 Rdg Project Manager -HNicolaras JStolz BGrimes (Emerg. Preparedness only)
OELD EJordan, IE ACRS-10 PMorriette NRC Meeting
Participants:
HNicol aras BBernero LRubenstein RJones HLi GLainas JStolz THuang LPhillips AThadani EChelliah JShea
CONCLUSIONS (CONT) o OTHER PERSPECTIVES NOT USEFUL WHEN RCPs ARE RUNNING OR RC VENTS ARE OPEN EQUIPMENT/CONTROL ROOM SPACE IS AT A PREMIUM THE RCIM SYSTEM IS PARASITIC IN THAT IT USES PLANT RESOURCES AND OPERATOR TIME WITHOUT PROVIDING AN EQUITABLE RETURN 34
RClf45S
~osr S
- 4. -2 3
35
STATUS o IMPLEMENTATION SCHEDULE PROVIDED BY 9/6/84 LETTER o CURRENTLY ON SCHEDULE o FINAL DESIGN DESCRIPTION - JULY, 1985 o EOP TECHNICAL GUIDELINES DUKE SUBMITTAL - MARCH, 1986 NRC APPROVAL - JULY, 1986 o IMPLEMENTATION LETTER UNIT 1 - NOVEMBER, 1986 UNIT 2 - MARCH, 1987 UNIT 3 - MARCH, 1986 o INSTALLATION COMPLETED - JUNE, 1987